Continuity mistake: The heels on Barbara's shoes appear and disappear throughout the movie.
Continuity mistake: While Batman and Robin are at Arbagast's home, the phone rings so Robin gives Arbagast the handset. When they realise it's Belson on the line, in a closeup Robin clicks the machine base to record the conversation. The problem is that in this closeup the handset is still in its base, even though Arbagast is still holding it talking to Belson. (00:42:45)
Continuity mistake: On the burning oil rig, when Robin and Barbara pull Mr. Freeze out from underneath the rubble, Barbara is missing her shoe and blue sock in this shot. (00:54:20)
Continuity mistake: Batman is hit by a falling piece of debris as he tries to save Freeze. He seemingly lets just go a button (or something) of the bat-rope gun, since it's still in hand, but a moment later he is dramatically reaching down calling Freeze's name and the hand is empty. He then stands, bat-rope in hand. (00:59:05)
Continuity mistake: In the room where Nora is stored, Barbara smashes with a pipe the bottle on the table. The liquid is spread to one side in the first shot, in a circle in the following. In the next shots, more inconsistencies appear (liquid appears to be leaking off the table, only to show later a half-circle nowhere near to any of the table edges). (00:34:45)
Continuity mistake: Barbara escapes traveling inside what is shown as a straight ventilation pipe, the closest intersection to her left being practically all the way to the back of the room with one to the right somewhere in between. Magically once Belson slips past the grate she has a left opening from a T juncture to escape into, right behind her. (00:33:25)
Continuity mistake: Barbara slips through the air conditioning conduit into the room next to her cell. Freeze uses his gun to cut her escape path. We see that the icy spikes are past the vent, since Belson opens a grid right before them, but when Barbara kicks the stalagmites loose, Belson pops up behind (or from) them. (00:33:30)
Continuity mistake: During the fundraiser, glasses of relevant guests (the woman in the red dress when she is introduced to Bruce, the stock broker when he is dragged away) disappear conveniently off-camera. It's quite a stretch to assume they found a waiter or a place to place the glass when they were not in frame (especially in the group of three women in front of the doors).
Continuity mistake: Batgirl roundhouse kicks one guy in the park. In the background, the victim has her left arm down, but it's up in the following shot. In that shot her walkman is also missing the cable linking the headset to it (it is there when Batgirl helps her stand later, same camera distance). (00:12:35)
Continuity mistake: The movie gets a lot of details right when it shows the establishing shot of the exterior of the fundraiser event Bruce Wayne goes to after the initial action; perfect continuity with the car models and people in the crowd ascending the stairs. But somehow, it has three people standing in front of the teal car, instead of 'just' two. (00:11:40)
Continuity mistake: Belson releases the mooring line to take off with the boat, and we see the rope slip away in close-up. Too bad that in the shot that follows the ignition, the boat is still moored, or at least the line is still in place. (00:55:35)
Continuity mistake: After beating the two robbers up, Batman and Robin dump them in a pile of trash on the sidewalk. That pile of trash was not there when the car turned the corner and crashed in front of the grocery store. (00:10:35)
Continuity mistake: When Dick gets slapped away from Freeze by the bear, he sits up; in the background there's one of the many dudes in red tie and cream colors, but the man was not there a moment earlier. (00:24:25)
Continuity mistake: At the hospital, Gordon issues orders to Montoya, then turns around to talk to Bullock. The stick in his mouth goes from the right corner to the left between shots. (00:30:25)
Continuity mistake: Robin looks with binoculars out of the right side of the bat-wing plane, and spots the oil rig...which is directly in front of it and a bit to the left. (00:47:40)
Continuity mistake: Freeze picks up the pills Barbara Gordon slapped out of Dr. Belson's hand. The pills are scattered in his palm differently between shots. (00:29:40)
Continuity mistake: Konak rips the tube off the anesthetic gas canister, but the next time the room is seen, the whole tank is on the ground. (00:46:55)
Continuity mistake: Batman deals with one of the jewelry robbers pulling him out of the car. Robin uses the bat-rope to grab the one that is running away; when he's running, just before he's caught by the rope he passes by a manhole to his right. When Robin's gun drags him throughout street, the manhole is on his left. (00:10:15)
Continuity mistake: The flower decal on Barbara's dress changes colour in some scenes.
Continuity mistake: Barbara's earrings change shape and color through the rest of the movie.
